SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd3ca9f51f70cc1b82e97e4684166d7fab1801377b212355a66e6bcf6ca56cd8' 
  AND token = 'AWkMrVFiAg7w7V70iZgJ3Jq1pvEW2iBxK+dCPIEaFQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}